PROJECT SUMMARY Recent changes in population patterns of tobacco use in youth and adults underscore the potential substitution of other menthol tobacco products for cigarettes in the face of a ban on menthol in cigarettes. The increased use of cigars and pipe tobacco in youth following the 2009 ban on flavored cigarettes is particularly important given that flavored filtered little cigars are often indistinguishable from cigarettes and flavored pipe tobacco can be used to make roll-your-own cigarettes. Mentholated pipe tobacco (for roll-your-own cigarettes, mRYO), menthol filtered little cigars (mFLC), and non-menthol cigarettes (nmC) appear to be plausible substitutes for menthol cigarettes. The goal of the current study is to examine the abuse liability and substitutability of these potential menthol cigarette substitutes using an in-laboratory and ad libitum outpatient mixed design. Eighty current menthol cigarette smokers (n=40 aged 18-24 years, n=40 aged 25+ years) will complete a three-phase study: in Phase 1, utilizing a randomized crossover design, participants' will complete 4 smoking sessions, smoking a different product each session to examine each product's abuse liability, demand, and topography. Products will include participants' usual brand menthol cigarette (UBMC) as well as 3 commercially-available alternatives, including mFLC, an mRYO product, and preferred non-mentholated cigarette (nmC). In Phase 2, to assess uptake, changes in subjective effects, and use over time, participants will select their preferred study product from Phase 1 and instructed to completely substitute the product for their UBMC for one week. Participants will complete ecological momentary assessments (EMA) during this period to more accurately assess substitution and perceived effects in real-time. In Phase 3, participants will complete a final in-lab visit to assess the substitutability of their preferred product from Phases 1 and 2, under simulated ban conditions using a progressive ratio task. In all phases, multiple domains of abuse liability will be assessed, including product administration (in-lab topography and EMA self-report measures), product liking/craving and withdrawal suppression (in-lab and EMA self-report). This study will be the first to estimate the substitutability of potential menthol cigarettes substitutes in adult smokers, which could impact the health benefit of a public health standard banning menthol in cigarettes. It will evaluate characteristics and perceptions (e.g., satisfaction, taste) of these products that may increase the likelihood of substitutability. Findings from this study will provide key information on the potential unintended consequences of a ban on menthol in cigarettes (i.e., the extent to which these substitutes would appeal to and be used by existing menthol cigarette smokers). They may also inform how FDA treats other non-cigarette tobacco products used as menthol cigarette substitutes in future proposed rulemaking, for example, extending the ban to menthol filtered little cigars or menthol pipe tobacco.